Water recycling

Design a system that can purify 300 gallons of water from soap, then determine the size of the tank and providing the water purification method and process, the water will be reused for water sprinkling to cool a certain area.

1- Draw the system in AutoCAD

2- Show all formulas/ integration/ other methods

3- The time needed to fill the tank

4- The system should not be continues it should be stored in the tank (patches)